Control device for automatic transmission

Abstract

There is provided a control device for an automatic transmission configured to automatically shift a transmission of a driving force of a motor in response to a driving state. The automatic transmission includes a synchromesh mechanism configured to couple gear pairs and a rotary shaft to transmit the driving force of the motor to the gear pairs and a switching apparatus configured to switch a coupling state of the gear pairs and the rotary shaft. A preload control unit is configured to operate the switching apparatus to apply a preload to the synchromesh mechanism when a shift transmission request is detected. A shift control unit is configured to operate the switching apparatus to apply a shift load greater than the preload to the synchromesh mechanism after the preload is applied to the synchromesh mechanism.

What is claimed is: 
     
       1. A control device for an automatic transmission that automatically shifts a transmission of a driving force of a motor in response to a driving state and includes: a rotary shaft; a plurality of gear pairs provided on the rotary shaft; a synchromesh mechanism configured to couple the gear pairs and the rotary shaft to transmit the driving force of the motor to the gear pairs; and a switching apparatus configured to apply a load to the synchromesh mechanism by an actuator to switch a coupling state of the gear pairs and the rotary shaft when a shift transmission request is detected, the control device comprising:
 a preload control unit configured to operate the switching apparatus to apply a preload to the synchromesh mechanism when the shift transmission request is detected; and 
 a shift control unit configured to operate the switching apparatus to apply a shift load greater than the preload to the synchromesh mechanism after the preload is applied to the synchromesh mechanism; 
 wherein the preload is applied to the synchromesh mechanism for a predetermined time period from a time point at which the shift transmission request is detected to a time point at which an automatic clutch configured to transmit and interrupt the driving force between the motor and the automatic transmission is released. 
 
     
     
       2. A control device for an automatic transmission that automatically shifts a transmission of a driving force of a motor in response to a driving state and includes: a rotary shaft; a plurality of gear pairs provided on the rotary shaft; a synchromesh mechanism configured to couple the gear pairs and the rotary shaft to transmit the driving force of the motor to the gear pairs; and a switching apparatus configured to apply a load to the synchromesh mechanism by an actuator to switch a coupling state of the gear pairs and the rotary shaft when a shift transmission request is detected, the control device comprising:
 a preload control unit configured to operate the switching apparatus to apply a preload to the synchromesh mechanism when the shift transmission request is detected; 
 a shift control unit configured to operate the switching apparatus to apply a shift load greater than the preload to the synchromesh mechanism after the preload is applied to the synchromesh mechanism; and 
 a clutch stroke detection unit configured to measure a clutch stroke amount of an automatic clutch configured to transmit and interrupt the driving force between the motor and the automatic transmission upon completion of control of applying the preload, and a preload learning unit configured to learn the preload when the clutch stroke amount exceeds a predetermined range so that the clutch stroke amount gets within the predetermined range.